Magnetic phonograph



July 1 1924. 1,499,521

w. HAGEMANN MAGNETIC PHONOGRAPH Filed May 29, 1922 v s 7 14 L Mme/Mar;

' Patented July '1, 1924.

UNITED STATES 1,499,521 PATENT oFI-lcs.

WALDEKAB EAGEEANN, OF BEBLIN-LIGH TBFELDE, GEBHANY, ABBIGHOB 'I'O V01HABOHINEN-AKTIENGEBELLS OHAFT, 01 BERLIN, Gm.

MAGNETIC PEONOGBAPH.

Application filed May 29, 1822. Serial No. 504,574.

To all whom it may concern Ije it known that I, Wamnuan Haas- MANN, acitizen of the Republic of Germany, residing at Berlin-Lichterfelde,Germany,

have invented certain Improvements in Magnetic Phonographs, of which thefollowing is, a specification.

,Phonographs of the Poulsen type, in which the sound vibrations arerecorded magnetically upon a fine traveling steel wire, depend, for thestrength and the purity with which the sounds are reproduced, on the seed of. the wire: the higher the speed of t 1e wire, within certainlimits, the better the reproduction. Good results have not so far beenobtained with a speed lower than three metres er second. As the machinema be required to reproduce a speech of hal an hours or an l-ioursduration, it is evident that a wire about 10,000 metres long and ofconsiderable wei ht would be required for this purpose. a manipulationof such a bulk movin at a high speed, is connected with diflicu ties,articularly when the machine is used for dictating urposes and has to behandled by a technica ly untrained office staff. It is essential,therefore, that the wire reels and their crating mechanism should beconstructed with great care so that a sudden stoppage and reversal ofthe movement can be accomplished with ease and certaint It is moreoveressential that me chanica vibrations and consequent extraneous noisesshould be eliminated, and this is hardly possible with the usual snallreels of about cm. diameter which have to revolve with a great velocityand which therefore are a t to set up vibrations, in the bearings, thatinterfere with and hinder the recordin and the reproduction of thesounds.

%he object of the present invention is to produce an apparatus of thiskind by means of which the wire can be run at the necessary speedwithout causing mechanical vibrations and without involvin diflicultiesin the manipulation of the mac ine, andthe invention consists inarranging two reels loosely on the same shaft, one at each side of aloose drivin pulley to which either can be coupled pulley.

by a s ight axial, relative displacement, the

wire being led over a guide ulley from the loose reel to the one coupledto the driving Means are provided for an automatic brakin of the reelsas soon as the coupling is re eased.

By this arrangement the reels can be made large enough to'produce a wiremotion of about 3 metres per second at a reel speed of from 3. to 4revolutions r second. At this speed there will be no etrimentalmechanical vibrations, and a sudden stoppa e and reversal of the reelscan be effected wit out jerks and without undue strain on the wire andon the mechanism.

In the accompanying drawings the invention is illustrated by way ofexample,

Fig. 1 representing a side view of the arrangement, partly in section,and

Fi s. 2 an 3, horizontal sections of slightly di erent constructions ofthe same, showingrthe driving ulley in different positions.

we wire ree s 1 and 2 are rotatably but not slidably arranged on arigidly supported shaft at opposite sides of a driving pulley 3 which iscapable of rotar as well as of a slight axial movement. T esound-recording wire 8 is led over a guide pulley 10 from one reel tothe other and passes through a magnetic element 9 by means of which thesound is recorded and reproduced. The ulley 10 is held in a fork 16 thestem of w ich is slidably guided in a bracket 17 a spring 18 beingarranged on the-stem so as to suport the pulley and keep the wire inuniorm tension. The element 9, together with the bracket 17 and wireguides 19 are carried by a base plate 20 which is secured to the freeend 0 a supporting arm 11 which is pivoted at 21 so that it can beoscillated for coiling the wire uniformly on the receiving reel. The arm11 is oscillated by a heartshaped cam 13 which revolves with a shaft 12,motion being imparted to the latter from the shaft 15 by means of ashaft 14 and suitable cars.

A driving pulley 3 receives motion direct from a motor 22 and can becoupled to either reel for winding the wire onto it, the other ulleybeing rotated in the opposite direction ythe unwinding of the wire. Thecouplin of the drivin pulley to either reel is pre erablyeifecte bymeans of axially arranged electro-magnets mounted symmetrically in thereels, the pulley 3 is made entirely or partly of iron so as to beattracted to the reel whose magnets are energized. The magnets 4 of thereel 1 are connected to a ring 23, and the ma ets 5 of the reel 2, to aring 24. The windlngs of the ma ets are connected to terminals to whichcurrent is w and may be provided with supplied by means of suitablesliding contacts. The reel 1 is also fitted with friction elements 6,and the reel 2 with similar elements 7. These friction elements, whichare sha d like bufiers, are actuated by. springs an bear normally, withsli ht iressure, a ainst the driving pulley 3 so -iat t 051088 movementsare opposed and interdendent, are held stationary by the pulley. a oneset of magnets is energized, however, the pulley will be attractedthereto, as shown in 2, and ap lied to one set of its friction e ementswit increased force, thefrictional hold of the opposite frictionelements being weakened or released so that the reels can rotate, onewith the pulley and the other in the opposite direction. As soon as thema ets areswitched off, the ulley moves bac to the position shown in 3and stops the movement of the reels. ven if the current is switched ofidirect from one set of magnets onto the other, the sto ping and reversalof the movement of the e ectric motor 22 thus controlled, though quick,will be suiiiciently gradual for eliminating any jerks or anyoverstrainin of the wire.

The slightly increa tension on the wire, and consequent adjustment ofthe pulley 10 in opposition to the sprin 18, at the stopping of thereels, can be uti ized for the operation of additional brakes controlleby means of levers from the fork 16. The'reels may be adapted for axialdisplacement instead of the riving pulley, and the friction elements aswell as the magnets may be connected to the pulley instead of to thereels-with the same result.

The reels 1 and 2 can be of difierent sizes, detachable, flangedrims inwhich to aecommodatethe wire. Such a construction is shown insonstructed according to the invention, the apparatus, besides beingnoiseless in operation, will require very little driving power.

I ii h h h t 1. ma etic one a avin wo revolubly m o unted r 'eels a dagtedto car ry the record wire, a revolubly mounted driven member,friction means carried by said reels and adapted to'normally restrainany movement thereof relative to said driven member, and means adapted'to move said driven member with res ectto said reels so as to increasethe hol of said friction means on one of said reels and decrease it onthe other. l

2. A magnetic phonograph having two means for engaging adapted to carrya record wire,

revolubly mounted reels adapted tocarry the record'wire, friction meanscarri by said reels and adapted to normally restrain the movementthereof, a revolubl mounted driven member adapted to positively driveone of the said reels at a time,'the movement of said driven member topositively drive one of said reels being ada ted to cause the lesseningof the frictional old of said frie tion means on that reel which is notbeing positively driven.

3. A magnetic phonograph having a sta-. tionary shaft, two se aratedreels revolublyr mounted on the sai stationary shaft and adapted tocarry a record wire, guiding means for the said record wire located!intermediate said reels, the said wire Being adapted to be so wound onthe said reels that if one of said reels is revolved so as to wind upthe record wire, the other reel is caused to revolve in the oppositediree tion, a driving pulley revolubly mounted on the said shaftintermediate the said reels and means mounted on said reels andcooperable with said driving ulley for rotation of the reels and means aa ted to laterally move the said pulley on tlie said-'shaft so as tocause it toengage either one of said reels and cause the ositiveactuation thereof.

4. A magnetic phonograph having a sta-* tionary shaft, two revolziblereels adapted to carry the record wire and mounted on the said shaft,each of said reels having electroma etic means connected thereto, adrivin pu ey intermediate the said reelsand made of iron or the like,ther'said pulley being adapted to move on the said shaft when it isattracted by the electro-ma etic means on one of said reels, the saidufi:

e reel towards which it is actua ed to cause the revolution of the saidghee}: h h h .5. agnetic p onograp a'vin a stationary shaft,,two searated reels re volubly mounted on the sai stationa shaft and idingmeans for the said record wire loca inter- .mediate said reels the saidwire being adapted-to be so wound on the said reels that if one of saidreels is revolved so as to wind up the record wire, the other reel iscaused to revolve in the opposite direction, and a driving pulleyrevolubly mounted on the reel shaft.

A WALDEMAR HAGEIANN. Witnesses:

E. HOLTZERMAN, Amos Sonaonnnn.

y cooperable with

